How can one distinguish whether the hardships a girl experiences are due to her shortcomings in her religion or if they are a trial and tribulation from Allah?

A Muslim recognizes his shortcomings in obedience through knowledge, hence he must learn the obligations and prohibitions. The way to attain God's love is by fully performing the obligatory duties, and then by increasing in supererogatory acts, as stated in the Hadith (definition) Qudsi: "My servant does not draw near to Me with anything more beloved to Me than what I have enjoined upon him, and My servant continues to draw near to Me with supererogatory deeds until I love him." Strive to increase in supererogatory acts of worship such as prayer, charity, and fasting, after performing the obligatory duties and avoiding the prohibitions. Also, frequently supplicate for the companionship of the righteous, avoid the idle, and increase in the remembrance of God.